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ESA 1 - Body Logistics > Types Of CT > Flashcards

Flashcards in Types Of CT Deck (15)
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1
Q

What are the 2 types of CT proper? Which is the most abundant?

A
  • Loose CT (most abundant)

- Dense CT

2
Q

Compare the structure of loose and dense CT proper.

A

Cell no. :
~ loose - many
~ dense - few (nearly all fibroblasts)

Fibres:
~ loose - sparse collagen fibres
~ dense - many collagen fibres

Ground substance:
~ loose - abundant (viscous, gel-like consistency - important role in transport, diffusion)
~ dense - little

3
Q

Where is loose connective tissue primarily located?

A
  • Beneath epithelia (e.g. Superficial layer of dermis and submucosa of colon) - facilitate diffusion.
  • Around small blood vessels
  • Associated with epithelium of glands
    ~ sites where pathogens can be challenged and destroyed by the cells of the immune system
4
Q

What are the 3 types of loose CT?

A
  1. Areolar: most common form, beneath all epithelial layers.
  2. Adipose: limited extracellular space but many adipocytes.
  3. Reticular: dominated by reticular fibres, e.g. In glands.
5
Q

What is the function of loose connective tissue?

A

Allows free movement with minimal resistance.

6
Q

What are the 2 types of dense CT?

A

Regular

Irregular

7
Q

Compare regular and irregular dense CT.

A

Collagen fibres are arranged:

  • regular - densely packed in parallel bundles (fibroblasts between bundles)
  • irregular - densely packed in bundles oriented in various directions (fibroblasts between bundles)

Withstands stress:

  • regular - in a single direction
  • irregular - in multiple directions

Located in:

  • regular - tendons, ligaments and aponeuroses
  • irregular - submucosa of intestine and deep layers of dermis
8
Q

How are collagen bundles in regular dense CT arranged in tendons and ligaments?

A
  • Tendons (bone to muscle): lie in a parallel, densely packed formation in line with the tensile force exerted by the muscle.
  • Ligaments (bone to bone): densely packed in parallel arrangement but undulate, and are arranged in fascicles, separated by loose CT.
9
Q

What is an aponeurosis?

A

Flat sheet of regular CT with bundles of fibres in one layer arranged at 90 degree angle to those in adjacent layer.
E.g. Lumbar aponeurosis or in abdominal wall.

10
Q

What is the role of adipose tissue?

A
  • Fat storage (fuel reserve)
  • Thermal insulation
  • Shock absorption
11
Q

What are the 2 types of adipocyte tissue?

A
White fat (most adipose tissue)
Brown fat
12
Q

What is the difference between white and brown adipocyte tissue?

A

White:

  • uniocular cells - almost entirely filled by a single fat droplet
  • cytoplasm displaced to cell rim and nucleus to one side

Brown:

  • multiocular cells - contain many lipid droplets
  • central nucleus
13
Q

Why do uniocular adipose cells appear empty in typical H and E stained, wax-embedded preparations?

A

Toluene and xylene used in tissue preparation have dissolved away the lipid.

14
Q

Where is brown adipose tissue found?

A
  • Close to scapula, sternum and axillae, esp. in newborn.

- Upper chest and neck of adults.

15
Q

Why are brown adipose cells brown, and what process are they important in?

A
  • Due to rich vascular supply and abundant mitochondria - high respiratory capacity for the generation of heat.
  • ‘Non-shivering thermogenesis’ important for babies.